Sight glass for a radiator



May '25, 1965 T. A. PIASECKI v SIGHT GLASS FOR A RADIATOR Filed Nov. 30, 1961 I l EHO! 70 1/ an E lllmflh ll Ira/anion 1 60mm lipdas kc' United States Patent 3,184,971 SIGHT GLASS FOR A RADIATOR Thomas A. Piasecki, Racine, Wis, assignor to Modine Manufacturing Company, a corporation of Wisconsin Filed Nov. 30, 1961, Ser. No. 156,085 3 Claims. (Cl. 73-334) This invention relates to an apparatus for viewing a liquid coolant in a radiator system.

In radiator systems, particularly of the closed high pressure type, it is difficult to determine when sufficient coolant liquid is present in the system. This problem is successfully solved by the present invention wherein a sight glass is provided in one portion of the radiator system together with means for providing a liquid-gas interface viewable through the sight glass in order to determine when liquid is present. This provision of the interface is important as after the radiator cooling system has been in use for a while, such as in an automobile, bus or the like, the glass becomes dirty so that it is difi'icult to determine whether the inner side of the glass is in contact with liquid or with gas such as air. This difliculty does not exist with the present invention because of the provision of the permanent liquid-gas interface when the radiator system has sufficient liquid cool-ant.

One of the features of this invention therefore is to provide an apparatus for viewing the coolant liquid in a radiator system and particularly a closed radiator sys tem including means for providing a liquid-gas interface viewable through the sight glass together with means for maintaining this interface even under conditions of high liquid flow through the radiator system.

Other features and advantages of the invention will be apparent from the following description of one embodiment thereof taken in conjunction with the accompanying drawings. Of the drawings:

FIGURE 1 is a semi-diagrammatic perspective view partially broken away of a portion of a radiator system including the apparatus of this invention.

FIGURE 2 is an enlarged fragmentary, vertical, sectional view through a portion of the radiator system of FIGURE 1 and taken substantially along line 22 of FIGURE 1.

In the embodiment illustrated in the drawings there is provided a radiator system of the closed high pressure type including an upper tank lit and a core shown diagrammatically at 11. This core which forms no part of the present invention is illustrated diagrammatically as a rectangular block but of course is made up of the usual parallel coolant liquid tubes and heat transmitting fins. Mounted in the top tank and facing forwardly of the radiator is an indicator 12 which of course is an apparatus for viewing the coolant liquid on the interior of the tank 10 and thus in the radiator system of which the tank 10 and core 11 are parts.

As shown in enlarged section in FIGURE 2 for clarity of illustration, the indicator apparatus 12 comprises a metal housing 13 having an inwardly projecting rounded part 14 and an enlarged substantially circular rim flange 15. The housing 13 extends inwardly through an opening 16 in the tank 10 with the rim flange being positioned on the exterior of the tank.

Held by the circular rim flange 15 is a circular fiat sight glass 17 that is held at its edges by means of a pair of rubbery gaskets 18 and 19 that are compressed together with an edge 20 of the glass 17 therebetween by means of a metal load distributing Washer 21 held in place by a snap ring 22 that in turn is held by the turned-in edge 23 of the rim flange 15. The rim flange adjacent the housing '13 is provided with a sealing bead 24 curved outwardly to 3,l84,97l Patented May 25, 1965 is indicated generally by the arrows 25. Thus, in FIG- URE 2 because of the location of the section line 22 of FIGURE 1 it is evident that the direction of flow of liquid 26 is from the observer through the plane of the drawing. The coolant liquid 26 completely fills the top tank or header 10 when the radiator system is in operation and therefore in FIGURE 2 the tank is illustrated as being completely filled. When the radiator system is not in operation the liquid level will fall slightly. During the operation of the system the flowing liquid in the tank 10 will be distributed in downward flowing paths indicated by the arrows 27 into the radiator parallel tubes (not shown) for cooling of the liquid in the customary manner.

In order to provide a liquid-gas interface the housing 13 is provided with an upper opening 27 and a lower opening 28. When the radiator system is in operation there is always a component of flow of liquid in a current into the housing 13 by way of the lower opening 28, upwardly within the housing and out through the upper opening 27. This component of flow in the current that is determined by the position of the openings 27 and 28 and in general is along a line connecting these openings is caused in the following manner. As can be noted from an inspection of FIGURE 2, the distance between the upper part of the housing 13 containing the opening 27 and the adjacent portion 29 of the tank 10 is smaller in cross-sectional area than is the distance between the other portions of the housing 13 and the adjacent portions of the tank 16. This generates a Venturidike effect to reduce somewhat the liquid pressure opposite the opening 27. This small reduction in liquid pressure causes the component current flow between the openings 27 and 28 as indicated by the arrows 30.

Also, as can be seen in FIGURE 2, the opening 27 is positioned beneath the top of the housing 13. This provides a trap closed at the top for entrapping a body 31 of gas which is primarily air. This gaseous body 31 above the liquid body 32 within the housing 13 provides a liquidgas interface 33 that is viewable at all times through the glass 17. The position of the interface within the radiator system containing sufiicient liquid coolant is always determined by the upper edge of the upper opening 27. Furthermore, the gaseous body 31 is always kept at a constant level when the coolant liquid is suflicient by entrapped gases indicated by the bubbles 34 that are carried by the current 30 through the lower opening 28 into the housing 13. In order that some of these bubbles will pass upwardly due to their buoyancy into the gaseous body 31, this body is located vertically above at least a portion of the current 30.

In order to prevent the lower opening 28 from being blocked or partially blocked by any solid matter in the coolant liquid 26, this opening is made larger than the upper opening 27. The size of the lower opening 28 is of course not important in governing the rate of liquid flow through the housing 13, as this rate is controlled by the upper opening 27 which because of its upper location is less subject to partial blockage by solid material. To further reduce the chances of blockage or partial blockage of the lower opening 28, it is placed on the downstream side of the housing 13. As mentioned earlier, the direction of liquid flow is generally from the observer into the plane of the drawing so that it is obvious that the opening 28 is on the downstream side.

As can be seen from the above discussion of the embodiment of the invention, the gaseous body 31 which is primarily air is protected by the housing 13 so that it can not be swept out by the liquid flow in the tank 10. In addition, it cannot be swept out by the relatively small current within the housing 13 between the openings 28 and 27 because this current Whose intensity is governed by the size of the opening 27 is much too weak. Thus,

under all conditions of operation, there is always provided the liquid-gas interface 33,,so long as the system contains sufiicient liquid coolant, that can be easily viewed through the glass 17. As mentioned earlier, this interface is important in this respect as if there were only liquid behind the glass it would be very difiicult if not impossible to tell if this were liquid or gas after the sight glass had become dirty.

The liquid-gas interface will of course vary depending upon whether the radiator system is in operation and upon the temperature and the amount of the "liquid. However, so long as there. is suflicient liquid in the system there can never be substantially less volume of the gas in the gaseous body 31 than that shown as this minimum amount is determined by placement of the upper opening 27. The minimum volume is not important so long as the liquidgas interface33 is positioned so as to be viewable through the sight glass 17.

The lower opening 28 constitutes an entrance into the housing .13 while the upper opening 27 constitutes an exit. This entrance and exit are linearly aligned at an angle to the vertical and it is this location of the openings which in general determines the positioning of the current 30 which of course also flows at an angle to the vertical.

While I have shown and described my invention as related to the embodiment shown in the accompanying drawings, it is my intent-ion that the invention be not limited by any of the details of description, unless otherwise specified, but rather be construed broadly within its spirit and scope as set out in the accompanying claims.

I claim:

'1. In a radiator system for a coolant liquid, apparatus for viewing said liquid comprising: a light transmitting member in said system for observing the interior of a part of the system; housing means adjacent said light transmitting member having a portion of said coolant liquid therein, the junction of the upperend of said housing means and the light transmitting member creating a gas trap adjacent said light transmitting member and in contact with said portion of liquid to provide a liquid-gas interface observable through said light transmitting member; and means for maintaining a current of liquid, carrying bubbles, in said housing coolant liquid portion, said means for maintaining said current including an element so located as to transfer bubbles from said current to said gas trap to maintain gas in said body.

2. The app-aratusof claim 1 wherein said means for maintaining said current of liquid comprises means forming a current entrance to said housing, and. means forming a current exit from said housing adjacent said gas trap.

3. The apparatus of claim 2 wherein said means forming said current exit is at a higher level than said means forming said current entrance so that a line between the entrance and exit is at an angle to the vertical to determine said current location, said gas trap being located substantially vertically above a portion of said current for the collection of rising gases carried throughsaid entrance by said current. 1

ISAAC LISANN, Primary Examiner. 

1. IN A RADIATOR SYSTEM FOR A COOLANT LIQUID, APPARATUS FOR VIEWING SAID LIQUID COMPRISING: A LIGHT TRANSMITTING MEMBER IN SAID SYSTEM FOR OBSERVING THE INTERIOR OF A PART OF THE SYSTEM; HOUSING MEANS ADJACENT SAID LIGHT TRANSMITTING MEMBER HAVING A PORTION OF SAID COOLANT LIQUID THEREIN, THE JUNCTION OF THE UPPER END OF SAID HOUSING MEANS AND THE LIGHT TRANSMITTING MEMBER AND IN GAS TRAP ADJACENT SAID LIGHT TRANSMITTING MEMBER AND IN CONTACT WITH SAID PORTION OF LIQUID TO PROVIDE A LIQUID-GAS INTERFACE OBVERVABLE THROUGH SAID LIGHT TRANSMITTING MEMBER; AND MEANS FOR MAINTAINING A CURRENT OF LIQUID, CARRYING BUBBLES, IN SAID HOUSING COOLANT LIQUID PORTION, SAID MEANS FOR MAINTAINING SAID CURRENT INCLUDING AN ELEMENT SO LOCATED AS TO TRANSFER BUBBLES FROM SAID CURRENT TO SAID GAS TRAP TO MAINTAIN GAS IN SAID BODY. 